Semiconductor devices are used in a variety of electronic applications, such as personal computers, cell phones, digital cameras, and other electronic equipment, as examples. Semiconductor devices are typically fabricated by sequentially depositing insulating or dielectric layers, conductive layers, and semiconductive layers of material over a semiconductor substrate, and patterning the various layers using lithography and etch processes to form circuit components and elements thereon.
A metal oxide semiconductor field effect transistor (MOSFET) is one type of semiconductor device. Many power MOSFETs comprise diffused metal oxide semiconductor (DMOS) devices, for example, which are adapted to operate at relatively high voltages. Examples of DMOS devices include n-channel lateral DMOS devices and p-channel lateral DMOS devices.
DMOS and other high voltage devices present manufacturing challenges, because the high operating voltages cause hot carrier (HC) degradation over time, which shortens device life. Thus, what are needed in the art are improved structures for DMOS devices and methods of manufacture thereof.